Such agricultural square balers are already known to the person skilled in the art. WO 2011 053122 A1 for example describes an agricultural square baler with a parallelepipedal baling chamber. A plunger, driven by a main driving mechanism, is movably received along longitudinal axis of the baling chamber, with a feed inlet, through which crop material can be conveyed into the baling chamber to be compressed there by the plunger into bales. A duct is connected to the feed inlet for collecting crop material before it is batchwise stuffed into the baling chamber. A stuffer is provided for batchwise stuffing the collected crop material from the duct through the feed inlet into the baling chamber. The stuffer is operably associated with the duct and comprises a rotatable drive shaft, with at least one crank arm fixed to the drive shaft. Further the baler comprises a fork assembly comprising tines and at least one fork lever supporting the tines which is rotatably coupled to the at least one crank arm on the one hand and pivotably supported by at least one fulcrum of the stuffer on the other hand. Such a configuration of the fork assembly allows relative movement of the tines along at least a packer and a stuffer trajectory, as shown in the figures of WO 2011 053122 A1. The fulcrum is pivotably fixed to at least one pivotable member of the stuffer around a pivot for displacing the fulcrum along a predetermined fulcrum path to selectively move the tines along the respective trajectories. The pivoting of the pivotable member around the pivot to displace the fulcrum along the predetermined fulcrum path is driven by a fulcrum driving device which is mechanically independent of the main driving mechanism, i.e. not being linked to the main driving mechanism by mechanical links, such as bars, pistons, or gears to directly transfer any momentum of the main driving mechanism to the fulcrum driving device and/or the fulcrum.
However, in such a configuration the fulcrum driving device nevertheless needs to be synchronized with one or both of the main driving device and the drive shaft of the stuffer such that the desired trajectory is followed by the tines at the desired moment. Although a sensor is described for determining the position of the fulcrum along the fulcrum path and the state of the fulcrum driving means and a sensor is described for determining which type of trajectory is desired in function of the compression of the crop material received in the duct, WO 2011 053122 A1 remains silent on how the position of the fulcrum, determined by the fulcrum driving device, is coordinated with the rotation of the drive shaft in the baling chamber such as to obtain that the tines move along a predetermined desired trajectory, the desired trajectory being determined by the position of the fulcrum coordinated with the position of the plunger of the machine.
Therefore, it is an object of the current invention to provide means for coordinating the position of the fulcrum along the fulcrum path with respect to the rotary position of the drive shaft such as to obtain a predetermined trajectory for the tines to follow.
Thereto, the pivotable member is mechanically linked to the drive shaft by linking means of the baler provided for mechanically pivoting the pivotable member in relation to the rotation of the drive shaft.
Such a pivot member mechanically linked to the drive shaft by linking means of the baler has been found to allow an easy coordination of the position of the fulcrum along the fulcrum path with respect to the rotary position of the drive shaft such as to obtain a predetermined trajectory for the tines to follow.
Moreover, it has been found that such mechanical linkage is reliable, especially when compared to electronic systems.
Moreover, the linking means comprise at least a packer and a stuffer cam mounted to a cam shaft rotating together with the drive shaft, the cams comprising a predetermined respective circumferential surface surrounding the cam shaft, and a cam follower for following the circumferential surface of the cam for determining the distance of the circumferential surface of the respective cams with respect to the cam shaft and provided to mechanically transfer the determined distance of the circumferential surface of the cams with respect to the cam shaft in function of the rotation of the drive shaft to a position of the fulcrum along the fulcrum path such that the tines move along the packer and the stuffer trajectory respectively.
Such a configuration has been found to allow an easy and reliable coordination of the position of the fulcrum along the fulcrum path with respect to the rotary position of the drive shaft such as to obtain a predetermined trajectory for the tines to follow. Moreover, as the cam shaft and the drive shaft can be made to rotate together, preferably synchronously, for example using mechanical means, such as for example gears, etc. or for example when the drive shaft and the cam shaft are the same and the cam shaft thus is the drive shaft, a reliable mechanical coordination of the position of the fulcrum along the fulcrum path with respect to the rotary position of the drive shaft can be obtained.
The multiple cams have moreover been found to relatively easily allow different trajectories for the tines to follow. For example, it becomes possible to add and/or remove possible trajectories for the tines to follow by adapting, adding and/or removing cams to and/or from the cam shaft. Also, the change of trajectory for the tines to follow can be done easily by moving the cam follower across the surfaces of the different cams using an actuator allowing the cam follower and the cams to be moved with respect to each other. The actuator for example is part of the linking means.
DE 3437294 A1 describes a stuffer for a round baler, but also fails to disclose means for coordinating the position of the fulcrum along the fulcrum path, displaced by a pneumatic actuator, with respect to the rotary position of the drive shaft such as to obtain a predetermined trajectory for the tines to follow as it is not described.
EP 1 769 674 A1 describes a different way of creating different trajectories for the tines to follow. However, due to the lack of a movable fulcrum it has been found more difficult to provide the different trajectories for the tines to follow, for example due to the complex linkage linking the movement of the plunger to the movement of the stuffer although the drive shaft of the stuffer actually usually is relatively close to the drive of the plunger.
EP 0 636 308 A1 describes a stuffer for a square baler, and is related to allow the tines to follow a substantially identical trajectory with a different velocity of the tines along the trajectory. The pivotable member is mechanically linked to the drive shaft by linking means of the baler provided for mechanically pivoting the pivotable member in relation to the rotation of the drive shaft.